The present invention relates to reinforcement, particularly in connection with reinforcing elements for shoes and more particularly military and outdoorsmen's boots subject to rugged long-term use, water, oil and weather exposure.
In such boot or related application, the use of external adhesives is undesirable because (a) long-term usage tends to degrade such external adhesives, (b) slow, costly processing is entailed with latex adhesives, (c) critical time/temp/pressure relationships are often required, and (d) residual thermosensitivity of hot melt adhesives is a further handicap. The requirement is not completely met by ionic resin stiffening elements as described in U.S. Pat. No. 3,427,733 to Beckwith. Older more traditional materials such as the polyethylene reinforced fabric of U.S. Pat. No. 2,734,289 to Heaton et al., as well as cardboard or rubber, have also proven inadequate.
It is an important object of the present invention to provide moldable, stiff reinforcement which is water, oil, impact and weather resistant.
It is a further object of the invention to provide such a reinforcement which is self-adherent to a carrier surface to be reinforced thereby.
It is a further object of the invention to provide such a reinforcement of laminate form with the ability to process at high production rate and utilize inexpensive components.
It is a further object of the invention to provide such reinforcement affording a toughness, impact-resistance and stiffness, consistent with one or more of the preceding objects.